Yes, that makes sense
Lol strange analogy… Thoughts are non-physical, and a bit easier to handle than physical objects like cars, don’t you think? 
According to Western science yes. But dream yoga replaces the illusionary dreaming process with pure awareness, rigpa. This won’t kill you. On the contrary… Ofcourse this more spiritual view is not really acceptable for science.
Check out these books for detailed information:
Tenzin Wangyal - The Tibetan Yogas of Dream and Sleep
Norbu Namkhai - Dream Yoga and the Practice of Natural Light
I see what you’re saying Mystic, it makes sense I’ll try to look at the books
Interesting idea, Mystic.
In my experience, maintaining the dream world is very much a conscious activity. It requires direct focus and attention to remain stable, despite making use of several subconscious functions, such as sensory processing. From that point of view, it seems reasonable that focusing on clearing your mind of conscious thought would probably destabilize the world, leading to a loss of lucidity or premature awakening.
Then again, I guess it depends on the method involved, and extent of clarity. A great method of waking meditation involves focusing your attention towards a constant and external source, which allows you to more easily clear your mind of random thoughts, while still experiencing sensory input. It’s the exact opposite of WILD, in that the idea is to become ‘hollow’, and integrated with the environment around you rather than disassociating yourself from the world entirely. To that effect, it might actually help to stabilize the dream world by suppressing distractions and keeping you concentrated on perceiving the dream world.
If you clear your mind from random thoughts by waking meditation techniques (focusing on one external point as you mentioned), you still have thoughts. But now your thoughts act like a laser beam: random light consists of numerous short light beams which all have a different wavelength and length. Laser beams however consist of light beams which all have almost the same length and wavelength. Likewise, random thought consists of lots of individual thought elements which get mixed inside your brain. By focusing on one point, you can filter them out until only one strong “thought beam” remains. But the laser beam, that one strengthened thought, still exists. This may indeed purify/stabilize the dream environment as you said. But what if even that one thought beam is stopped? Premature awakening? Perhaps… We may not be accustomed to those kind of situations, so one can only guess how it would be to remain aware during the process of fully dissolving thoughts while in a LD.